Gareth's Random Blog of Fiddlings

Main menu

Tag Archives: Mechatronics

So after an amazing three months in Germany, I had to come back to the real world and finish off a Master’s Dissertation.

I got back to PE mid-December and had a week to finish off my testing before I left for the Cape for two weeks. I then had five more days in PE before I had to hand in my dissertation. Final hand-in date to still qualify for April graduation was 11 January, handing in after that date would mean I’d have to reregister for another year of studies, and would probably result in me doing a whole lot more work, not necessarily a bad thing.

But with 3 days to go I was still doing testing. Below you can see a clip I compiled of said testing. In the end I handed in a dissertation in time. Most of it had gone through a round of editing by both my gran and girlfriend, with slight input from my supervisor. I wasn’t completely happy with what I’d handed in, and could have done with another month to neaten up the report, read through it properly and get some proper feedback from my supervisor, but such is life, and what is done is done.

In any case, the following week I did a demonstration for the project initiators who were quite happy with the results and it will most likely be taken forward. There’s a second master’s project on the table which will be extending on my work, but the company in question are going to take the design to contractors with the plan of getting a commercial unit up and running. Exciting stuff, my supervisor was also quite happy and said from his side he doesn’t think there’ll be any problems, so know I just sit and wait for results from the external. If I hear before the end of March I’ll be surprised, but don’t know when I should start bugging my supervisor for answers :)

In the mean time I’ve moved another step further from the Cape to the city of East London where I’ve got an appointment at a large manufacturing plant for the next year. The work ought to be quite interesting as the factory’s busy with a rebuild, but it’ll be interesting to see where it goes.

Once I’ve had feedback on my master’s and have made any necessary changes I’ll put my full thesis up. I also have to write up a journal type article on the project so will post that whenever I get round to finishing it. In the mean time you can see my previous post on the project here.

or Mechatronic Engineering, humourously (but incorrectly) referred to as Megatronics at times. In Afrikaans Megatronika or MegatronieseIngenieurswese. What is it? What can you do with it? When I started studying I didn’t know, after 5 years I think I have a vague idea. So below I’m going to post what I know.

In it’s simplest form it’s a combination of Mechanical and Electronic Engineering. If I really don’t feel like explaining, I simplify it to robotics. This is certainly a large portion of Mechatronics, but by no means a limiting factor.

Mechatronics as a named profession is fairly new, but the idea has always been there. In the South African context, UCT have had an accredited BSc (Eng) Mechatronics course since 1997 (although how long it has actually been running is uncertain), NMMU a BEng since 2007 (first graduates) and Stellenbosch since 2005 [1]. Potchefstroom University (NWU) are apparently aiming to start a course in the next few years [2]. Although not offered in the BEng format, UKZN do offer Masters through their Mechatronics and Robotic Research Group [3]. [EDIT: added list of BTech degrees and Diplomas offered at the bottom of the post]

Mechatronics at Stellenbosch [2]

I completed my BEng Mechatronics at Stellenbosch University in 2011. The Mechatronics course was presented by the Department of Mechanical and Mechatronic Engineering in a four year course. The first two years were identical to that of those studying towards a BEng Mechanical. The first year course is identical for all engineering students. In the third and fourth years, the two courses still followed similar routes, with the Mechatronics course replacing several Mechanical courses with some courses presented by the Department of Electronic and Electrical Engineering. In third year these included Electronics and Computer System’s courses and fourth year Electronics and Electronic Design Courses. Losing out on some Strength of Materials and Thermo-Fluid Mechanics.

The department put it this way [6]

The most important difference between the mechanical engineering programme and the mechatronic programme is that mechanical engineers are equipped to develop mechatronic systems with existing controllers (computers, PLC’s, etc.), while mechatronic engineers are also equipped to develop specialised controllers (e.g. for embedded controllers) and the relevant electronics themselves.

At the time, the Head of Department felt that Mechatronics as an entity was still too new. Employers weren’t advertising for Mechatronic Engineers, and didn’t really know what to do with them when they did get them. This resulted in the close ties between the Mechanical and Mechatronic courses. I was often unhappy about this, having would of preferred more focus on the Electronics, but in the end it worked out. And the HoD’s opinions were/are valid.

When I chose Mechatronics, I didn’t know where I was going to work, I chose the course because it sounded interesting. It wasn’t until my final year that I found a direction to work towards. Course setups at different universities are going to be different, and will put emphasis on different subjects, that doesn’t necessarily make one better than the other. Either way you’re going to come out of it with a degree and a fair amount of knowledge. Most importantly though (and this is true for any engineering degree) is you’ll know how to learn.

I’m quite confident that specific things that I learn in my first year of work will be of more value to my career than a specific subject at varsity, but having struggled through several subjects, I know I can figure out most things that come my way. I know where to look and how to go about solving problems.

In my final year we were a class of 85 Mechanical/Mechatronic students, of which I’d say about 30-35 received their BEng Mechatronics in 2011.

Mechatronics at NMMU [2]

NMMU have a slightly different setup. Mechatronics is presented by the Mechatronics school of the Department of Engineering, the Built Environment and IT. Mechatronics is the only Engineering degree they offer. As such, first year physics and maths are taken alongside BSc students and after the first year, courses taken are aimed only at Mechatronics students. The format of the course is still identical to that of when it started giving a good balance of subjects. The University also offers an array of BTech degrees in other Engineering fields.

I’m currently pursuing my master’s degree at NMMU. Their 4th year BEng Mechatronics class has roughly 25 students in it and the 3rd year class about 30. First year applications are limited to 60, with the most recent 1st year class starting with 50 students. The Mechatronics department is currently sponsored by General Motors South Africa (who have a plant in PE) and also have close ties to the Volkswagen plant in Uitenhage.

Mechatronics in General

Mechatronics as a career is still finding its feet. Meaning many consider it a jack of all trades, master of none type of situation, and although the course may feel that way, it’s certainly not the end of the story.

Mechatronics isn’t a new field, it’s just finally been given a name. When you tell people you’re a Mechatronic Engineer they don’t know what that is. I had a month stint at a large production facility as part of vacation training and I was asked to choose between focusing on their Mechanical or Electrical divisions, eventually settling for a bit of time at each. But that’s how businesses in SA are structured. This will change.

Several Mechatronic Engineers that I know have taken up Automation maintenance posts. Nothing wrong with this, personally it’s not where I want to be. Contrary to this though, my first job next year will be in automation maintenance. I however plan to use this as a stepping stone into a design career.

Automation is fun, and whereas I am going into automation in a production sense, automation also relates to smaller and/or more technical situations. The recent landing of the Curiosity rover on Mars is a perfect example of Mechatronic systems. There are several elements here, from the automated landing system to the remote control of the device.

In the motor industry, systems such as traction control, ABS and ESP are all examples of Mechatronic systems. Heavily complicated systems that rely on the processing of data from sensors to enable control of actuators. As such a Mechatronic Engineer can make him/herself home in many different industries. These include the Automotive, Aerospace, Manufacturing, Medical and Communications Industries.

Mechatronic Engineers can register with ECSA to become Professional Engineers [4]. The industry is governed by the South African Institute for Mechanical Engineers. I don’t see Mechatronics separating from this tree any time soon. The degree, being accredited by ECSA also means that the degree will be recognised internationally in many countries thanks to the Washington, Sydney and Dublin Accords [5]

So what do you do when you have your degree? You do whatever you want. You’ll find something. I’m not aware of any of my colleagues who are currently not pursuing a post-graduate degree or are employed. Not all of them are in Mechatronic specific posts. Some have opted for more mechanical orientated jobs, while others have gone entirely into areas such as electronic design or programming. And that’s one thing, a degree in Mechatronic Engineering in no way limits you. Very few engineering degrees will actually.

After re-reading what I’ve written, I think I’ve put forward some information relating to Mechatronic Engineering, but it’s still left fairly vague, maybe it’s just because none of us know what we’re really doing :)

From xkcd.com

A National Diploma in Mechatronics (for registration as a Professional Engineering Technician) can also be had from the following institutions [7]:

Tshwane University of Technology

UNISA

Cape Peninsula University of Technology

A BTech in Mechatronics (for registration as a Professional Engineering Technologist) from [8]:

Tshwane University of Technology

UNISA

Cape Peninsula University of Technology

and to reiterate, a BEng, or BScEng (for registration as a Professional Engineer) [1]:

Stellenbosch University

University of Cape Town

Nelson Mandela Metropolitan University

Note: Although other institutions may offer courses in Mechatronics, or Mechanical Engineering with a focus on Mechatronic elements, the ones listed above are the only ones recognised by ECSA for registration as a mechatronic professional. Information was correct at time of posting, but may have changed since.

There are also several Universities of Technology and FET Colleges which offer courses in Mechatronics. CPUT is one of these institutions. Another training institution is Umbilo Training Specialists in Durban. They are running a free training course, once a month where anyone can come to learn more and expand their knowledge. Checkout their page for details.

For some more reading and a very complimentary view with some poignant remarks have a read here.

As part of my degree at Stellenbosch University I completed a project which can be seen here.

As part of my master’s degree at NMMU I completed a project which can be seen here and here.

This was the title of my final year project for my BEng (Mechatroics) degree at the University of Stellenbosch. It’s been a year, a loooong year, but at the same time it’s passed so quickly. I’ve probably spent more time on varsity work this year than in any other previous year, a combination of this skripsie, mechatronics and electrical design projects, interspersed between the year’s class requirements.

You can see a summary poster of the project here. And the full report here.

Skripsie is something very different to what we’ve done previously. We’re given a year to complete the project, which is a fairly long time. What I’ve appreciated is the fact that it’s the only major project we’ve been given to do individually. It’s not that I don’t like other people, it’s just that it’s sometimes nice to be able to do things my way. Most of the projects are put forth by lecturers, and they act as supervisors for the projects. I’ve been very fortunate with my supervisor and his continued support and enthusiasm for my project.

Final Product

So what is it? Well it’s basically a turret that is capable of continuous rotation. You get a bunch of pan/tilt cameras on the market, but they all stop after 360textdegree or less. The department I did my project with had purchased several Basler a311fc cameras to play with and desired a platform they could use for tracking. It’s a very nice camera, good quality and capable of fairly high capture rates (50fps @ 640×480, 132fps @ 320×240) and comes with some nifty software (Basler Pylon Driver) to control it. So the major issue was to transfer data and power to the camera. I looked at a couple of wireless solutions but for simplicities sake eventually went with slip rings. Picked up 2 slip rings (at quite a cost, well I was surprised at the expense) from Moog.

a slipring

Next issue was control. My control systems has never been the strongest, so decided to stick with some open loop control in the form of stepper motors. Picked up a 220Nmm and 440Nmm stepper motor to control the tilt and pan respectively. They’re bi-polar hybrid stepper motors with a 0.9textdegree step size. I drove them both in half-step mode effectively giving me 0.45textdegree accuracy. To drive them I made use of a combination of L297 and L298 ICs from ST.

The idea was to be able to control this all from a PC, so some software development and integration was also required. To bring it all together I made use of an Arduino Uno. I developed a GUI in Python which then communicated via a serial connection with the Arduino. I was originally going to use Java for this, but couldn’t get a serial connection running. Chatted to some friends who suggested Python and found this post with a nice example. For testing I also got hold of two AS5040 hall effect sensors from Austria Microsystems. These rotary encoders give a 1024bit resolution, effectively 0.35/textdegree. I managed to find some nice code for the Arduino to read the data via SSI over at RepRap.

CAD Model

This was also the first time I’ve had the opportunity to develop CAD models of something and have it built. We’ve done several machine design projects over the years, but they’ve all been conceptual only. I didn’t machine the stuff myself, but it was pretty cool when I built the thing, and compared it to my model, and it looked the same.

screenshot of the UI

So I handed in the final report on the project today. Unfortunately it’s not working 100% at the moment, and one of the motor driver circuits got damaged, so I need to repair that before my presentation in a few weeks time.

But until then, it’s 3 exams in 3 weeks, so ought to be pretty chilled. And I’m almost an engineer o/

This last semester has kept me busier academically than I’ve ever been before with the main culprits being our two large design projects as well as skripsie. And when i say busy, I mean spending hour after hour through weekends and public holidays in labs working to ensure that projects are complete. The thing is, is that I was having fun. Well to an extent. There were many times where tiredness and frustrations got the better of me, but the moments of joy when something worked were incredible.

The Mechatronics project was interesting, but not my favourite. In theory it was quite simple, but a bit more tricky in application. In essence we were told we needed to take 2 tanks and then have user inputs allowing one to set the desired water level and temperature in both tanks. We were limited by only being able to pump fresh water into tank 1, and only being allowed to place a heating element in tank 1. Our end setup comprised of a kettle as our first tank which we pumped fresh water into. The second tank was placed at a lower height to allow water to flow from the first tank to the second tank. Water could be pumped into tank 1, and then solenoid valves were used to allow water to flow into the second tank, or allow water to flow from either of the tanks back into the reservoir.

Floats were connected to potentiometers to give us a height/volume reading of the water and supplied thermocouples gave us accurate temperature readings. The entire system is then linked by a Schneider Electric Modicon momentum Soft PLC and Tutorbox. During the term we were given tutorials on how to use Wonderware’s InControl and InTouch software to control the PLC. The project does rather throw one into the deep end though. The training for the PLC doesn’t really explain it’s functionality and very little focus is given on actually programming in the software. Instead we’re taught to make use of RLL programs to control the system.

But the scope of our project was far too complicated to rely on RLL programs. Instead we chose to figure out how to use the other supported Structured Text Language instead. We downloaded some tutorials and beginners guides, but so many of the things we tried gave us compiler errors in the software, so in the end we resorted to a trial and error method, hacking our way through. Till now I’ve only ever really coded in Objected Orientated programming languages, which I don’t really feel STL complies to. This amongst with many other small nuances lead to me hating the programming side of this project. Fortunately one of the group members took to it with vigour.

Our final demo went reasonably well, everything worked to an extent and the “judges” seemed impressed even if the system didn’t run as smoothly as we had hoped.

And onto Digital Design. The basic story is that we were building remote controlled gate units. We had a main board which comprised of a 16 character LCD screen on which we displayed a menu controlled by 5 push buttons. There was a serial->USB converter to communicate with a computer, some EEPROM to store some data a PWM controller to control the “gate” motor, an optical sensor for determining the state of the gate, a triac to turn an AC driven light on/off a buzzer to annoy people and an IR receiver.
We then had a remote with an IR diode for transmitting data, 2 buttons and its own EEPROM for good measure. Both units were based around the Renesas R8/C27 microcontroller programmed in C via Renesas’ HEW software. Fun with that spawned this fan group page. Apart from a few resistor values that had to be calculated, the component design aspect was pretty much handled for us, the big issue was understanding how these components worked, and then getting them to play nice with the rest of the components.

We were given the components every 2nd week or so, and built up our boards slowly as we acquired and programmed each successive piece. In the end we had a board on which each component worked by itself, but then it was time to pull everything together and get the software programmed to work as required. Quite a challenge. This was truly the subject which has taught me the most, or in which I feel I’ve learnt the most. It was work that I hadn’t ever really done, but had always interested me, and although it really is a tough course, and a bit of a trial by fire, I’m glad how it turned out.

As an interesting fact, last year somewhere close to 50% of 4th year Mechatronic Engineers failed the subject. And I can believe that. Although we are given some preparation in the form of a semester of Electronics and 2 semesters of Computer System, the work we do is completely new and requires a different way of thinking and time dedication second to none.

Although a bit dramatic, it quite often feels like. Nothing has frustrated me as much as the unproductive hours spent on this project. We’re busy compiling a report on the project to hand in on Monday, so will post some schematics and pictures then.And then it’s on to exams for 3 weeks, a bit of holiday/skripsie work for 2 weeks, vacation work in East London for 4 weeks and back to Stellenbosch for my last undergrad semester.